chapter 2 stats

A useful way to determine the number of classes (k) in a frequency distribution of n items is the "2 to the k rule" Which of the following correctly describes the rule?

k is the smallest number such that 2k>n

To divide data with a high value of H and a low value L into k classes, the class interval must be:

at least (H-L)/k

In the cumulative frequency polygon shown, about how many observations are there between a value of 200 and 250?

50

Regarding frequency tables and frequency distributions, which one of the following is true?

Both show the number of observations in each class.

In a frequency polygon the points are plotted at the intersection of the class frequencies and the

class midpoints

Place the following steps used in constructing a frequency distribution into correct order.

1.) Decide on the number of classes. 2) Determine class width. 3) Set individual class limits. 4) Tally the number of observations in each class.

Suppose you are trying to summarize a data set a maximum value of 70 and a minimum value of 1. If you have decided to use seven classes, which one of the following would be a reasonable class interval?

10

Given below are limits for two consecutive classes for a frequency distribution that summarizes student grade point averages. Which set of limits is best?

3.000 up to 3.250 3.250 up to 3.500

A business statistics instructor teaches a class with 83 students. Suppose he would like to create a frequency distribution to summarize their 83 final exam scores. Using the "2 to the k rule," how many classes should used?

7

What is the final step of creating a frequency distribution?

Count the number of observations in each class

Which of the following is not a useful practice in setting individual class limits for a frequency distribution?

Excluding outliers that cause the interval to be too wide.

Which of the following graphs are used to summarize quantitative data? Select all that apply.

Frequency Polygon Histogram

Which of the following is true regarding raw data?

Raw data are simply a listing of data before summarizing it.

Which of the following practices is commonly used in setting class limits for a frequency distribution?

Rounding the class interval up. Placing excess interval width equally in the two tails in distribution.

Which of the following features is not part of a histogram?

The frequency of occurrence of a nominal variable

Suppose a cumulative relative frequency distribution is used to summarize n observations. The cumulative relative frequency for the last class will always be

equal to one

The number of observations in each class is called the class

frequency

In using the "2 to the k rule" to determine the number of classes for a frequency distribution, what is the meaning of the variable k?

k is the smallest number of classes such that 2k is greater than the number of observations

Which of the following are true regarding the class midpoint? Select all that apply.

It best represents the values in a class. It is halfway between the lower limits of two consecutive classes. It is halfway between the upper limits of two consecutive classes.

Which of the following features is an advantage that the features in an advantage that the frequency polygon has over the histogram?

It can directly compare two or more frequency distributions

Which of the following operations is true regarding relative frequency distributions?

The relative frequency is found by dividing the class frequencies by the total number of observations.

Which of the following can be observed from a histogram. Check all that apply.

The shape of distribution. The approximate number of observations. The concentration of the data. The spread of data.

The value show on the vertical axis of a cumulative frequency polygon for a particular class is found by:

counting the number of observations less than the upper limit of the class.